Influence of the Crosslinking Ion’s Valence on Hydrogel’s Final Properties

Interpenetrating hydrogels with advanced stiffness were prepared from the iron-alginate and cross-linked poly(acrylamide). Multiple approaches were combined in order to prepare hydrogels with mechanical properties required for various biomedical applications.

Final properties of these materials were studied in terms of their water content and elastic modulus. Special attention was paid to describe the relationship between final properties and the nature of alginate crosslinks (bivalent or trivalent ions).

Parameters such as concentration and nature of the alginate, crosslinking density of poly(acrylamide) network, IPN formation procedure were studied and adapted for obtaining the desired materials. Compared to the simultaneous synthesis procedure, the two-step process was found to be absolutely necessary for effective miscibility of two highly crosslinked networks.

PDF LINK

Foundations of Chemical Kinetic Modeling, Reaction Models and Reactor Scale-Up

The majority of manuscripts dealing with the subject of chemical reactions, detailed chemical reaction models, and chemical kinetics present the material with strong mathematical foundations and emphasis.

This is the reason for the conceptual approach taken in this manuscript where the result of the application of theory in the form of mathematical models is not the major consideration but the understanding of the fundamental concepts behind the complex mathematical theories.

Even today, unfortunately, the industrial professional performing the design of a chemical reactor may not have the practical experience in Mathematics as well as Quantum Mechanics or Physical Chemistry to fully understand the implications of the mathematical formulism. This is especially true of the mathematical methods used in Quantum Chemistry as well as quantum mechanics applications to the estimate of rates of chemical reactions.

PDF LINK

Introduction of In Silico Chromatography

Molecular interaction (MI) is fundamental phenomena in nature. Chromatography is a tool to quantitatively measure the degree of molecular interactions. The qualitative explanation has been performed using solubility factors. The quantitative explanation is achieved using computational chemical calculation (In silico).

The molecular interaction forces are combination of solubility factors, and can be obtained as van der Waals, hydrogen bonding and electrostatic energy values after molecular mechanics (MM2) calculations. Simple study can be done using small molecules. The model analyses should help to quantitatively understand the chromatographic retention mechanisms. When one small molecule is replaced to a macro molecule, (chromatography model phase), we can quantitatively analyze chromatography retention time with the retention times of standard compounds.

Furthermore, when the macro molecule is a protein, we can study affinity level of proteins. In addition, the apc calculated using MOPAC program indicates the enzyme reactivity. Prediction of boiling point, dissociation constant, and albumin-drug binding affinity were demonstrated as practical applications of in silico chromatography.

PDF LINK

Need To Study On a New Nontoxic Material to Relieve Cytokine StormCaused By Viral Pandemics

Need To Study On a New Nontoxic Material to Relieve Cytokine StormCaused By Viral Pandemics

Is There A Role for Radiotherapy In Experimental Therapeutic DrugDevelopment

Is There A Role for Radiotherapy In Experimental Therapeutic DrugDevelopment

Biosorption of Neodymium by Selected Photoautotrophic and Heterotrophic Species

Rare earth elements (REEs) consist of the lanthanides plus yttrium and scandium. Global demand for REEs in 2015 was estimated to 210,000 tons. These elements are chemically very similar and randomly distributed in nature. Hence, their production is difficult and challenging due to many byproducts such as thorium, uranium, heavy metals and acidic waste waters.

Moreover, they can be found together in bulky rocks, so their separation is sophisticated. The classical exploitation of REE sources currently pollutes nature heavily. Due to that and the fact that around 97% of the worldwide needof REEs are provided by China, making REE-consuming industries excessively dependent on rationing and the rising world market prizes, there is a great interest in alternative and environmentally friendly methods for delivering these elements. Read more...................

Prevention of Dust Hazards Affecting Workers in Hard Coal Mines

This paper presents the results of the tests conducted with the ZWILKOP ZW-10 dust control preparation (Patent P. 394235) used in the air and water sprinkler systems at mining facilities.

The tests aimed to assess the inhalation exposure of the mining personnel to respirable/1 and inhalable2/dust fraction and to chemical agents when using ZWILKOP ZW-10 (MSDS 2013) preparation.

This publication contains the results of the measurements performed to evaluate concentrations of the hazardous chemical substances: 2-(2-butoxyethoxy)ethanol and 2-ethylhexan-1-ol, which are the components of the ZWILKOP ZW-10 preparation, and respirable1/ and inhalable2/ dust fractions at mining personnel workstations.

PDF LINK

Foundations of Chemical Kinetic Modeling, Reaction Models and Reactor Scale-Up

Even today, unfortunately, the industrial professional performing the design of a chemical reactor may not have the practical experience in Mathematics as well as Quantum Mechanics or Physical Chemistry to fully understand the implications of the mathematical formulism.

This is especially true of the mathematical methods used in Quantum Chemistry as well as quantum mechanics applications to the estimate of rates of chemical reactions.

Another important consideration that may be difficult during the composition of reaction models is the generation of elementary chemical reactions to explain the formation of products and most important trace components some of which may be of concern due to pollution of the environment.

PDF LINK

A New Optical Sensor for Selective Monitoring of Nickel Ion Based on A Hydrazone Derivative Immobilized on the Triacetyl Cellulose Membrane

A new highly selective optical sensor was prepared by de-esterification of triacetyl cellulose transparent film and chemical immobilization of 1-acenaphthoquinone 1-thiosemicarbazone (L) on it.

The absorbance variation of immobilized 1-acenaphthoquinone 1-thiosemicarbazone on hydrolyzed cellulose acetate film of upon addition of 1.5 × 10-5 mol L-1 aqueous solutions of Zn2+, Pb2+, K+, Cu2+, Ag+, Ni2 , Cd2+, Ca2+, CrO4 2-, Hg2+, Co2+, Mn2+, Cr3+, S2 O3 2-, Mg2+, Na+, Al3+, Tl+ and Fe3+ indicated a substantiality much larger variation for the Nickel ion in compare to other studied ions.

Consequently, the new hydrazone derivative L possesses a high selectivity towards this metal ion. Influences of various experimental parameters on Ni2+ sensing, including the reaction time, the solution pH and the concentration of reagents were studied.

PDF LINK

Advances and Changes in the Techniques of Multi- Dimensional and Comprehensive Chromatography and When Coupled with Mass Spectrometry

This review covers the principles of two dimensional gas and liquid chromatography (2DGC and 2DLC) and briefly introduces the theory accounting for the increase in separation resulting from a greater peak capacity than for the one dimensional (1D) mode.

The advance in the techniques from multi-dimensional to comprehensive chromatography is discussed. The more recent development of multi-dimensional chromatography ion mobility mass spectrometry receives a mention to highlight the added dimension of molecular size and shape (molecular collision cross section) as an enabling tool for increasing component separation and peak capacity.

Although both the techniques of 2DGC and LC are described the focus is on the environmental and food applications of 2DGC, principally when coupled to mass spectrometry, with TOFMS and HRMS as prime examples.

PDF LINK

Nanotechnology in Preparation of Semipermeable Polymers

Chemical engineering as a branch of engineering applies physical, chemical and life sciences with applied mathematics and economics to design large-scale processes for converting raw materials into useful forms and products. Advancement in chemical engineering helps in optimizing the industrial outputs.

Chemical Engineering Journal is an open access international peer reviewed publication that publishes recent advances on these topics. Seven research articles and a review article have been published in volume 6 issue 2 of the journal. Ahamed et al. in their research article described the synthesis of aminoguanidyl-chitosan imprinted polymers (AGCIPs) for the recovery of precious metals like gold and silver from aqueous solutions. The author found that AGCIPs are effective in absorbing gold and silver from the solutions and also the polymer can be regenerated for reusing up to five times without change in the adsorption capacity.

Characterization of Royal Jelly by Electrospray Ionization Mass Spectrometry Fingerprinting

Royal jelly is an apicultural product, fed to the queen bee and consumed by humans as a health food and traditional medicine; its beneficial effects on human health have been the subject of several studies. As royal jelly is obtained in small amounts and reaches a high market price, it could be adultered with other cheaper substances. As it is prone to degradation at room temperature, lyophilization is used to prolong its shelf life. 

Due to the complex composition of royal jelly, several different parameters need to be evaluated to determine of freshness, purity and quality; consuming an appreciable amount of sample and time. Electrospray ionization mass spectrometry (ESI-MS)fingerprinting was carried out in the negative ion mode on a high resolution FT-ICR mass spectrometer; marker compounds were identified by comparison of their high resolution mass with data from literature. ESI-MS fingerprinting was capable of characterizing natural, lyophilized, degraded and adultered samples of royal jelly, and indicate marker compounds for each set of samples, with the aid of Principal Component Analysis. 

Adding Analytical Metrics to the Production and Aging of Whiskey Using a Protein Sensor Assay

Differentiation of complex biological samples in a rapid and reliable manner is a major challenge for analytical chemists and biologists alike. Recently, the utility of a protein-based assay (PSA) for differentiating wine varietals, cellular stress, and urine was demonstrated.

The assay uses a highly abundant protein in mammalian blood, serum albumin (SA), as a sensor that works by binding a subset of the small molecules present in a sample.

Analysis of the selectively bound molecules by liquid chromatography mass spectrometry (LC-MS) improves the ability to differentiate and categorize samples compared to direct analysis by LC-MS.

PDF LINK

Chemical, Structural and Elemental Characterization of Biosorbents Using FE-SEM, SEM-EDX, XRD/XRPD and ATR-FTIR Techniques

Given the increased emphasis on the use of lignite and coconut shell-based activated carbon fiber (ACF), powdered oyster shell, and acidified powdered Pinus densiflora (Japanese red pine) pine cones as the prominent biosorbents for anionic surfactant sodium dodecyl sulfate (SDS) adsorption, there have been surprisingly few studies undertaken to characterize the chemical, structural, and elemental composition of aforementioned samples.

The main aim of this study, therefore was to investigate the chemistry, structure, and mineralogy of lignite and coconut shell-based activated carbon fiber (ACF), powdered oyster shell, and powdered Pinus densiflora pine cones samples using multiple characterization techniques including x-ray diffraction (XRD)/x-ray powder diffraction (XRPD) analysis, field emission scanning electron microscopy (FE-SEM), multiple internal reflectance (MIR) or attenuated transform reflectance.

Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy coupled with energy dispersive x-ray (SEM-EDX). In addition, the samples were treated to determine the iodine number or iodine index for the characterization of the three samples.

A New Optical Sensor for Selective Monitoring of Nickel Ion Based on A Hydrazone Derivative Immobilized on the Triacetyl Cellulose Membrane

In the recent years, pollution of the environment by heavy metals has received considerable attention. Nickel is a moderate toxic element compared to other transition metals.

However, it is known that inhalation of nickel and its compounds can lead to serious problems, including respiratory system cancer. Moreover, nickel can cause a disorder known as nickel-eczema. Nickel is an excellent alloying metal in steel industry and is the metal component of the enzyme urease and as such is considered to be essential to plants and some domestic animals.

This metal normally occurs at very low level in the environment, so sensitive methods are needed to detect it in most environmental samples. Thus, the development of simple methods for selective determination of nickel in trace amounts in different matrices is critical.

PDF LINK

Qualitative and Quantitative Analysis of Dan-Deng-Tong-Nao Capsules by HPLC-DAD-MS/MS

“Dan-Deng-Tong-Nao capsules” (DDTNCs) is a commonly used traditional Chinese formula medicine, which is prepared (extracted, purified and combined) from four commonly used Chinese herb drugs, including Radix Salvia miltiorrhiza, Radix Pueraria lobata, Erigeron breviscapus and Rhizoma chuanxiong.

DDTNCs have the ability of activating blood circulation to dissipate blood stasis, removing obstruction in the meridians and heart-nourishing effects. It was usually used for the treatment of apoplexy and the syndrome of apoplexy involving both collaterals and meridians caused by obstruction of collaterals by blood stasis.

Chemical constituents of the four component herbs of DDTNCs have been intensively studied. However, little is known about the chemical composition of DDTNCs, and the current analysis methods could not reflect the quality of it.

PDF LINK

An Optical Sensor For Monitoring Nickel Selectively Using Immobilization Technology

In the recent years, pollution of the environment by heavy metals has received considerable attention. Nickel is a moderate toxic element compared to other transition metals.

However, it is known that inhalation of nickel and its compounds can lead to serious problems, including respiratory system cancer. Moreover, nickel can cause a disorder known as nickel-eczema. Nickel is an excellent alloying metal in steel industry and is the metal component of the enzyme urease and as such is considered to be essential to plants and some domestic animals.

This metal normally occurs at very low level in the environment, so sensitive methods are needed to detect it in most environmental samples. Thus, the development of simple methods for selective determination of nickel in trace amounts in different matrices is critical.

PDF LINK

Evaluation and Characterisation of Composite Mesoporous Membrane for Lactic Acid and Ethanol Esterification

Solvents play a major role in all stages of industrial manufacturing sector. The environmental and toxicological effects of solvents have become important in chemical processes.

Because environmental problems have threatened the natural order including climate change and global warming, a lot of research is being carried out to find environmentally safe chemicals and processes. Lactic acid is the simplest hydroxycarboxylic acid with an asymmetric carbon atom. It can be obtained from biomass, petroleum and coal.

Copolymers and polymers of lactic acid are known to be eco-friendly and are compatible due to their degradability mild products, which makes them desirable as an alternative petrochemical polymer.

PDF LINK

Thermodynamic Calculation of a Heat of First-Order Phase Transitions

A transition heat is the most important characteristics of first-order phase transitions. Black was first who discovered in 1762 that in the transfer of water to vapor, some quantity of heat is absorbed, which he termed the latent evaporation heat.

In spite of more than the two-hundred-year period of the heat transfer concept existence there are no analytical expressions relating the transition heat with other parameters of phase transitions.

For example, the fundamental "Physics Encyclopedia", articles devoted to the transition heat, evaporation heat, and so on, comprises no formulae but only tables of experimental data. One can also mention monographs which have no relationships except for the conventional definition of the transition heat λ=TΔS.

PDF LINK

Modern High Performance Liquid Chromatography

This year, our worldwide chromatography community will be celebrating 50 year anniversary of high performance liquid chromatography. 13 August 1966 Csaba Horvath and Seymour Lipsky are published in Nature their report about first high pressure separation of organic compounds on a self-packed ion exchange chromatographic column, entitled: “Use of Liquid Ion Exchange Chromatography for the Separation of Organic Compounds”.

Year latter was introduced first commercial HPLC instrument by Waters. To emphasize the major technological difference from typical at that time low pressure applications, HPLC meaning was “High Pressure Liquid Chromatography”.

Before 1966 liquid chromatography utilized either gravity flow or low pressure pumps for an eluent delivery. Typical applications there are protein separations using ion exchange and gel filtration, inorganic anion exchange chromatography and normal phase separations of various organic substances using self – packed silica columns.

PDF LINK

Chemical, Structural and Elemental Characterization of Biosorbents Using FE-SEM, SEM-EDX, XRD/XRPD and ATR-FTIR Techniques

Given the increased emphasis on the use of lignite and coconut shell-based activated carbon fiber (ACF), powdered oyster shell, and acidified powdered Pinus densiflora (Japanese red pine) pine cones as the prominent biosorbents for anionic surfactant sodium dodecyl sulfate (SDS) adsorption, there have been surprisingly few studies undertaken to characterize the chemical, structural, and elemental composition of aforementioned samples.

The main aim of this study, therefore was to investigate the chemistry, structure, and mineralogy of lignite and coconut shell-based activated carbon fiber (ACF), powdered oyster shell, and powdered Pinus densiflora pine cones samples using multiple characterization techniques including x-ray diffraction (XRD)/x-ray powder diffraction (XRPD) analysis, field emission scanning electron microscopy (FE-SEM).

Multiple internal reflectance (MIR) or attenuated transform reflectance – fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy coupled with energy dispersive x-ray (SEM-EDX). In addition, the samples were treated to determine the iodine number or iodine index for the characterization of the three samples.

PDF LINK

Growth Rate and Morphology of a Single Calcium Carbonate Crystal on Polysulfone Film Measured with Time Lapse Raman Micro Spectroscopy

The phenomenon of calcium carbonate crystal growth from aqueous solutions on surfaces widely occurs in systems where carbonate and bicarbonate ions are present, such as in domestic systems, waste and drinkable water treatment systems or industrial apparatus where water is used.

Crystal growth leads to the formation of mineral scale which reduces the performance of membrane materials in equipment. The scale development is affected by factors such as: pH, super-saturation index, temperature, water composition etc.

The process of scaling and crystal growth includes the following stages:The induction period involve nucleation and crystal growth, and The mineralizing crystals and others particles transportation from the bulk and its adhesion to the surface,and Ageing of crystals at a surface, for instance due to recrystallization and dehydration.Other components present in a mineralizing solution could increase or decrease the crystal growth rate by adhesion to crystal surfaces.

PDF LINK

Mixed Matrix Membranes for Adsorption Application

Mixed matrix membrane (MMM), a currently popular research field, is a type of membrane formed by incorporating fillers in polymer matrix. Its preparation procedures mainly involve with only blending and phase inversion.

According to its structure, MMM can typically be divided into two categories. The first one is with a dense structure, mostly developed for the applications in gas separation, pervaporation, fuel cell, and so on. The fillers employed for improving the MMM performance in this category are usually inorganic nanomaterials (zeolite, carbon nanotube, metal organic framework, etc.) with specific features (shape, pore size, surface interaction, etc.).

The other category is with a porous structure, specially designed for adsorption purpose. Micro-to-nano-size particles with functionality are regularly adopted as the fillers for this kind of MMM to provide the adsorptivity with target solutes.

PDF LINK

Arrested Precipitation Technique for Synthesis of Chalcogenide and Oxide Thin Films

Interest in the use of photo electrochemical solar cells for low cost energy conversion has led to an extensive research in the search for novel and suitable thin film semiconductor materials. The techniques presently used for synthesis of mixed metal chalcogenide and oxide thin films are CBD, MOCVD, spin coating, electro deposition, spray pyrolysis, sputtering, crystal growth, and chemical bath deposition.

All these deposition techniques require specific sophisticated instrumentation. In this regard APT is more attractive and relatively inexpensive presently used by us for deposition of mixed metal chalcogenide and oxide thin thin films.

In the present investigation we attempt to prepare mixed metal chalcogenide and oxide thin films by arrested precipitation technique. The purpose of work is to establish and optimize the growth condition to produce these thin films.

PDF LINK

Boron Isotope Fractionation in Bell Pepper

Stable isotope systems of major nutrients like oxygen or carbon have been successfully used to trace the provenance of plants and food products. The boron  isotope system is of great interest in plants because B was found to be an essential micronutrient in plants occurring predominantly in the cell walls and acts as a strengthening component.

Boron has two stable isotopes, 11B (~80% abundance) and 10B (~20% abundance) and its isotope amount ratio n(11B)/n(10B) is reported as delta (δ)-values (eqn. 1), referring to the Standard Reference Material (SRM®) 951 from the National Institute for Standards and Technology (NIST; Gaithersburg, USA).

In aqueous solutions, B exists as uncharged trigonal boric acid B(OH)3 in acidic media or as tetrahedral borate ion B(OH)4 - in alkaline media. The lower vibrational energy of the trigonal coordinated boric acid species causes a preferential incorporation of the heavier B isotope compared to the tetrahedral species  leading to boron isotope fractionation in nature.

PDF LINK

Isotopic Abundance Analysis of Biofield Treated Benzene, Toluene and p-Xylene Using Gas Chromatography-Mass Spectrometry

Benzene, toluene and p-xylene isomers are nonpolar organic liquid, volatile, aromatic and the most important constituents of gasoline. Benzene, toluene and p-xylene are one of the important sources of energy being utilized with petrol/gasoline for vehicle fuel.

All three compounds are produced during the process of making gasoline and other fuels from crude oil as well as in making coke from coal. Benzene have been used for long time in manufacturing plastics, detergents, pesticides, and other chemicals such as ethyl benzene, cyclohexane, nitrobenzene, chlorobenzenes and maleic anhydride.

Toluene has numerous commercial and industrial applications and was used as a solvent in paints, lacquers, thinners, glues, correction fluid, nail polish remover, and in printing and leather tanning processes. p-xylene has been used in adhesives industry, paint industry, and as manufacturing solvent in rubber industries.

PDF LINK

Biogeochemical Cycling of Nutrients and Thermodynamic Aspects

The term “biogeochemical cycles” is used in order to describe the transfer and transformation of matter and energy between the biosphere and the other active reservoirs of Earth namely the atmosphere, hydrosphere, and lithosphere.

During the functioning of a biogeochemical cycle, a series of molecular species which are essential for supporting life on the planet, also referred to as nutrients, are being constantly transported and chemically transformed. The main chemical elements making up the basic nutrients circulating within a specific biogeochemical cycle and which are involved in the structuring of complex bio-polymers (e.g. proteins, DNA, RNA, etc.) are C, N, S, P, and O.

A biogeochemical cycle is activated via coupling of the biosphere to nutrient fluxes supplied by specific sites or active centers on Earth (e.g. volcanoes and hydrothermal fields). Such sites/centers act as a constant source of matter (e.g. volatile chemical species) and/ or energy on the Earth surface, either on a regional or a global scale, which can be used by different living forms.

Prevention of Dust Hazards Affecting Workers in Hard Coal Mines

Prevention of dust hazards  and inhalation exposure of the mining personnel to chemical agents  are important issues influencing optimisation of OHS conditions at mining facilities. Increased coal extraction results in higher dust immissions at a workplace, posing an explosion hazard and leading to development of lung diseases in mining personnel due to the presence of free silica in coal dust.

The new air and water sprinkling solutions implemented in the mining industry  reduce substantially airborne dust pollution in mines.

However, water sprinkling systems commonly used at mining facilities are not effective enough in reducing dust immissions. Air dampeners are used to further improve OSH conditions as regards dust concentrations.

PDF LINK

Ionic Liquids Matrices for Laser Assisted Desorption/Ionization Mass Spectrometry

Room-temperature ionic liquids (RTIL) are molten salts with melting point below 100 °C. They have distinctive properties and thus they were used for catalysis, separations, mass spectrometry, and other.

They have been applied as ion pairing reagent for electrospray ionization mass spectrometry (ESI-MS), solvent for liquid-liquid extraction, stationary phases for chromatography and as solvents in electrochemistry. The materials have many properties that enhanced and improved the analysis using mass spectrometry.

In general, the typical mass spectrometer is consist of five parts; inlet for the sample, ion source, analyzer, detector and vacuum. The main roles of ionic liquids in mass spectrometry are mainly focused in the improvement of the analyte ionization, as solvent and as ion-pairing reagent for ESI-MS.The present review is a tutorial article for researchers who seek about the application of ionic liquids for mass spectrometry.

PDF LINK

Nanotechnology in Preparation of Semipermeable Polymers

Chemical engineering as a branch of engineering applies physical, chemical and life sciences with applied mathematics and economics to design large-scale processes for converting raw materials into useful forms and products. Advancement in chemical engineering helps in optimizing the industrial outputs.

Chemical Engineering Journal is an open access international peer reviewed publication that publishes recent advances on these topics. Seven research articles and a review article have been published in volume 6 issue 2 of the journal. Ahamed et al. in their research article described the synthesis of aminoguanidyl-chitosan imprinted polymers (AGCIPs) for the recovery of precious metals like gold and silver from aqueous solutions.

In the research article published by Shehu et al., the authors have successfully developed mesoporous membrane by using dip coated silica and zeolite for selectively removing Carbon dioxide from methane and to produce quality pipelines meant for natural gas. Shil et al. in their research article described the process of preparing Aluminum oxide from the industrial wastes by acid and alkali methods.

PDF LINK

Modern High Performance Liquid Chromatography and HPLC 2016 International Symposium

This year, our worldwide chromatography community will be celebrating 50 year anniversary of high performance liquid chromatography. 13 August 1966 Csaba Horvath and Seymour Lipsky are published in Nature their report about first high pressure separation of organic compounds on a self-packed ion exchange chromatographic column, entitled. “Use of Liquid Ion Exchange Chromatography for the Separation of Organic Compounds”.

Year latter was introduced first commercial HPLC instrument by Waters. To emphasize the major technological difference from typical at that time low pressure applications, HPLC meaning was “High Pressure Liquid Chromatography”.

Before 1966 liquid chromatography utilized either gravity flow or low pressure pumps for an eluent delivery. Typical applications there are protein separations using ion exchange and gel filtration, inorganic anion exchange chromatography and normal phase separations of various organic substances using self – packed silica columns. Isolation range was varied from analytical to preparative.

PDF LINK

Experimental Determination and Modeling of the Drying Curves of Eucalyptus camaldulensis

The aromatic and medicinal plants are more used for several applications in pharmacy, medicine and food processing therefore the necessity of their preservation. Eucalyptus camaldulensis is usually used for medicine for several aims such as anti-inflammatory of the respiratory tract.

In addition, Eucalyptus camaldulensis oil is an important, most popular and widely used essential oil. In order to preserve this seasonal plant, and make it available to consumers during the whole year, it undergoes specific technological treatments, such as drying.The leaves are perishable in nature because of high moisture content. For the effective utilization of the leaves, the postharvest processing aspect is important so that the quality of the leaves can be preserved with enhanced shelf life.

Dehydration is a useful method of preserving the leaves; it enhances the resistance of high humid products against degradation by decreasing their water activity. Conventional air drying is the most frequently used dehydration operation in food and chemical industry due to its controllable conditions and less dependency on climatic conditions. However, studies on the drying characteristics of Eucalyptus camaldulensis leaves are scarce in the literature.

PDF LINK

A Novel Catechol Electrochemical Sensor Based on Cobalt Hexacyanoferrate

Recent decades, considerable efforts have been invested in the determination of phenolic compounds in environmental, industrial, agricultural, and food fields [1,2]. Phenolic compounds are released into environment by a large number of industries, such as coal mining, oil refinery, paint, polymer and pharmaceutical preparation.

Phenolic compounds are secondary metabolites. They are not involved in growth and energy metabolism and are usually generated in response to environmental stress. Some of these phenolic compounds like phenol, hydroquinone, are also harmful to humans and animals. Catechol (CC, 1,2-dihydroxybenzene) is a phenolic derivative with several applications such as an antifungal preservative on potato plantations, a photographic and fur dye developer, and as an antioxidant.

Therefore, the determination of catechol is very important in environmental protection. Catechol undergoes oxidation under mild conditions to give benzoquinone. Benzoquinone is said to be antimicrobial, which slows the spoilage of wounded fruits and other plant parts. Catechol is produced by the reversible two-electron, twoproton reduction of 1,2-benzoquinone.

PDF LINK